import { act, renderHook, waitFor } from "@testing-library/react";
import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { getSettings, saveSettings } from "./settings";
import {
	classNames,
	formatTokens,
	relativeTime,
	useSessions,
	useToasts,
} from "./store";
import {
	FakeWebSocket,
	jsonResponse,
	mockFetchJson,
	seedSettings,
	stubReload,
} from "./test/setup";
import type { EventFrame, SessionListItem } from "./protocol";

const NOW = new Date("2024-05-01T12:00:00Z").getTime();

describe("relativeTime", () => {
	beforeEach(() => {
		vi.useFakeTimers();
		vi.setSystemTime(NOW);
	});
	afterEach(() => {
		vi.useRealTimers();
	});

	it("formats all buckets", () => {
		expect(relativeTime(null)).toBe("never");
		expect(relativeTime(NOW - 10_000)).toBe("just now");
		expect(relativeTime(NOW + 30_000)).toBe("just now");
		expect(relativeTime(NOW - 5 * 60_000)).toBe("5m ago");
		expect(relativeTime(NOW - 3 * 3_600_000)).toBe("3h ago");
		expect(relativeTime(NOW - 2 * 86_400_000)).toBe("2d ago");
	});
});

describe("classNames", () => {
	it("joins truthy parts", () => {
		expect(classNames("a", false, "b", null, undefined, "c")).toBe("a b c");
		expect(classNames()).toBe("");
	});
});

describe("formatTokens", () => {
	it("compacts with one decimal under 100, no decimal above", () => {
		expect(formatTokens(0)).toBe("0");
		expect(formatTokens(999)).toBe("999");
		expect(formatTokens(1000)).toBe("1K");
		expect(formatTokens(1234)).toBe("1.2K");
		expect(formatTokens(340000)).toBe("340K");
		expect(formatTokens(1250000)).toBe("1.3M");
		expect(formatTokens(1200000)).toBe("1.2M");
		expect(formatTokens(2500000000)).toBe("2.5B");
	});
});

describe("useToasts", () => {
	beforeEach(() => {
		vi.useFakeTimers();
	});
	afterEach(() => {
		vi.useRealTimers();
	});

	it("pushes a toast and removes it after TTL", () => {
		const { result } = renderHook(() => useToasts());
		act(() => result.current.push("hello"));
		expect(result.current.toasts.map((t) => t.text)).toEqual(["hello"]);

		act(() => result.current.push("second"));
		expect(result.current.toasts).toHaveLength(2);

		act(() => {
			vi.advanceTimersByTime(4000);
		});
		expect(result.current.toasts).toHaveLength(0);
	});
});

function listEvent(seq: number): EventFrame {
	return { v: 1, sessionId: "s1", seq, ts: 0, type: "message_end" };
}

describe("useSessions", () => {
	it("returns null when unconfigured", () => {
		const push = vi.fn();
		const { result } = renderHook(() => useSessions(push, true));
		expect(result.current).toBeNull();
	});

	it("first-run: inactive -> active starts the ws manager (A)", async () => {
		seedSettings();
		mockFetchJson(() => []);
		const push = vi.fn();
		const { result, rerender } = renderHook(
			({ active }: { active: boolean }) => useSessions(push, active),
			{ initialProps: { active: false } },
		);
		// gate is up: settings exist but the hook must not dial yet
		expect(FakeWebSocket.instances.length).toBe(0);
		expect(result.current).not.toBeNull();

		// gate saved: active flips true, the effect re-runs and starts the manager
		rerender({ active: true });
		await waitFor(() => expect(FakeWebSocket.instances.length).toBe(1));
		expect(result.current?.state).toBe("connecting");
	});

	it("seeds via REST, updates from session_list and spawn_status frames, refresh works", async () => {
		seedSettings();
		const sessions: SessionListItem[] = [
			{
				id: "s1",
				name: "one",
				online: true,
				busy: false,
			},
		] as SessionListItem[];
		const fetchMock = mockFetchJson((url) => {
			if (url.includes("/api/sessions"))
				return url.includes("/events") ? [] : sessions;
			return [];
		});
		const push = vi.fn();
		const { result } = renderHook(() => useSessions(push, true));

		expect(result.current?.state).toBe("connecting");
		await waitFor(() => expect(result.current?.sessions).toEqual(sessions));

		const sock = FakeWebSocket.last();
		act(() => sock.serverOpen());
		expect(result.current?.state).toBe("open");

		act(() =>
			sock.serverMessage({
				type: "session_list",
				sessions: [{ id: "s2", name: "two", online: false }],
			}),
		);
		expect(result.current?.sessions.map((s) => s.id)).toEqual(["s2"]);

		act(() =>
			sock.serverMessage({
				type: "spawn_status",
				jobs: [{ repo: "g/p", state: "cloning" }],
			}),
		);
		expect(result.current?.spawnJobs).toEqual([
			{ repo: "g/p", state: "cloning" },
		]);

		// refresh resolves to the fetched rows (S7) and re-seeds the list
		let out: SessionListItem[] | undefined;
		await act(async () => {
			out = await result.current?.refresh();
		});
		expect(out).toEqual(sessions);
		expect(result.current?.sessions).toEqual(sessions);
		expect(fetchMock).toHaveBeenCalled();
	});

	it("refresh failure pushes a toast and resolves to an empty list", async () => {
		seedSettings();
		mockFetchJson(() => {
			throw new Error("network down");
		});
		const push = vi.fn();
		const { result } = renderHook(() => useSessions(push, true));
		await waitFor(() =>
			expect(push).toHaveBeenCalledWith("sessions: network down"),
		);
		expect(result.current).not.toBeNull();
		let out: SessionListItem[] | undefined;
		await act(async () => {
			out = await result.current?.refresh();
		});
		expect(out).toEqual([]);
	});

	it("subscribe routes events frames for the session and detaches on unsubscribe", async () => {
		seedSettings();
		mockFetchJson(() => []);
		const push = vi.fn();
		const { result } = renderHook(() => useSessions(push, true));
		const sock = FakeWebSocket.last();
		act(() => sock.serverOpen());

		const seen: EventFrame[][] = [];
		let off: (() => void) | undefined;
		act(() => {
			off = result.current?.subscribe("s1", (events) => seen.push(events));
		});
		expect(sock.sent).toContain(
			JSON.stringify({ type: "subscribe", sessionId: "s1" }),
		);

		act(() =>
			sock.serverMessage({
				type: "events",
				sessionId: "s1",
				after: 0,
				events: [listEvent(1)],
			}),
		);
		act(() =>
			sock.serverMessage({
				type: "events",
				sessionId: "other",
				after: 0,
				events: [listEvent(2)],
			}),
		);
		expect(seen).toEqual([[listEvent(1)]]);

		act(() => off?.());
		act(() =>
			sock.serverMessage({
				type: "events",
				sessionId: "s1",
				after: 1,
				events: [listEvent(3)],
			}),
		);
		expect(seen).toHaveLength(1);
		expect(sock.sent).toContain(
			JSON.stringify({ type: "unsubscribe", sessionId: "s1" }),
		);
	});

	it("auth failure clears settings and reloads", async () => {
		seedSettings();
		mockFetchJson(() => []);
		const loc = stubReload();
		const push = vi.fn();
		const { result } = renderHook(() => useSessions(push, true));
		const sock = FakeWebSocket.last();
		act(() => sock.serverOpen());
		act(() => sock.serverClose(1008));
		expect(loc.reload).toHaveBeenCalled();
		expect(getSettings()).toBeNull();
		await waitFor(() => expect(result.current).toBeNull());
		loc.restore();
	});

	it("3 failed connects + 401 REST probe clears settings and reloads (S3)", async () => {
		vi.useFakeTimers();
		vi.spyOn(Math, "random").mockReturnValue(1);
		seedSettings();
		mockFetchJson((url) =>
			url.includes("/api/sessions")
				? jsonResponse({ error: "unauthorized" }, 401)
				: [],
		);
		const loc = stubReload();
		const push = vi.fn();
		renderHook(() => useSessions(push, true));
		const failConnect = (): void => {
			act(() => FakeWebSocket.last().serverClose(1006));
		};
		failConnect();
		act(() => {
			vi.advanceTimersByTime(500);
		});
		failConnect();
		act(() => {
			vi.advanceTimersByTime(1000);
		});
		failConnect(); // 3rd consecutive connect failure -> probe -> 401
		for (let i = 0; i < 8; i += 1) {
			// eslint-disable-next-line no-await-in-loop
			await act(async () => {
				await Promise.resolve();
			});
		}
		expect(getSettings()).toBeNull();
		expect(loc.reload).toHaveBeenCalled();
		loc.restore();
		vi.useRealTimers();
	});

	it("probe failing with a non-401 error never clears settings (S3)", async () => {
		vi.useFakeTimers();
		vi.spyOn(Math, "random").mockReturnValue(1);
		seedSettings();
		mockFetchJson((url) => {
			if (url.includes("/api/sessions")) throw new Error("daemon unreachable");
			return [];
		});
		const loc = stubReload();
		const push = vi.fn();
		renderHook(() => useSessions(push, true));
		const failConnect = (): void => {
			act(() => FakeWebSocket.last().serverClose(1006));
		};
		failConnect();
		act(() => {
			vi.advanceTimersByTime(500);
		});
		failConnect();
		act(() => {
			vi.advanceTimersByTime(1000);
		});
		failConnect();
		for (let i = 0; i < 8; i += 1) {
			// eslint-disable-next-line no-await-in-loop
			await act(async () => {
				await Promise.resolve();
			});
		}
		expect(getSettings()).not.toBeNull();
		expect(loc.reload).not.toHaveBeenCalled();
		loc.restore();
		vi.useRealTimers();
	});

	it("successful probe resets the failure counter, no clear (S3)", async () => {
		vi.useFakeTimers();
		vi.spyOn(Math, "random").mockReturnValue(1);
		seedSettings();
		let sessionsCalls = 0;
		mockFetchJson((url) => {
			if (url.includes("/api/sessions")) {
				sessionsCalls += 1;
				return [];
			}
			return [];
		});
		const loc = stubReload();
		const push = vi.fn();
		renderHook(() => useSessions(push, true));
		const failConnect = (): void => {
			act(() => FakeWebSocket.last().serverClose(1006));
		};
		const flush = async (): Promise<void> => {
			for (let i = 0; i < 8; i += 1) {
				// eslint-disable-next-line no-await-in-loop
				await act(async () => {
					await Promise.resolve();
				});
			}
		};
		failConnect();
		act(() => {
			vi.advanceTimersByTime(500);
		});
		failConnect();
		act(() => {
			vi.advanceTimersByTime(1000);
		});
		failConnect();
		await flush();
		// mount seed (1) + exactly one probe (2); nothing else
		expect(sessionsCalls).toBe(2);
		expect(loc.reload).not.toHaveBeenCalled();
		expect(getSettings()).not.toBeNull();

		// counter reset: two more failures stay under the threshold, no probe
		failConnect();
		act(() => {
			vi.advanceTimersByTime(2000);
		});
		failConnect();
		await flush();
		expect(sessionsCalls).toBe(2);
		loc.restore();
		vi.useRealTimers();
	});

	it("unmount closes the manager", async () => {
		seedSettings();
		mockFetchJson(() => []);
		const push = vi.fn();
		const { unmount } = renderHook(() => useSessions(push, true));
		await waitFor(() => expect(FakeWebSocket.instances.length).toBe(1));
		const sock = FakeWebSocket.last();
		unmount();
		expect(sock.closeCode).toBe(4900);
		expect(sock.onclose).toBeNull();
	});

	it("returned store object keeps identity when only unrelated state changes (S2)", async () => {
		seedSettings();
		// a stable list reference: only identity behavior is under test here
		const stable: SessionListItem[] = [];
		mockFetchJson(() => stable);
		const push = vi.fn();
		const { result, rerender } = renderHook(() => useSessions(push, true));
		await waitFor(() => expect(FakeWebSocket.instances.length).toBe(1));
		// let the mount-time seed settle
		for (let i = 0; i < 4; i += 1) {
			// eslint-disable-next-line no-await-in-loop
			await act(async () => {
				await Promise.resolve();
			});
		}
		const first = result.current;
		rerender();
		rerender();
		expect(result.current).toBe(first); // memoized, not a fresh object
	});

	it("store identity changes when the sessions list changes", async () => {
		seedSettings();
		let list: SessionListItem[] = [];
		mockFetchJson(() => list);
		const push = vi.fn();
		const { result } = renderHook(() => useSessions(push, true));
		await waitFor(() => expect(result.current).not.toBeNull());
		const first = result.current;
		const sock = FakeWebSocket.last();
		act(() => sock.serverOpen());
		list = [
			{
				id: "s9",
				name: "x",
				online: true,
				busy: false,
			} as SessionListItem,
		];
		await act(async () => {
			await result.current?.refresh();
		});
		expect(result.current).not.toBe(first);
		expect(result.current?.sessions.map((s) => s.id)).toEqual(["s9"]);
	});
});

describe("settings persistence used by the store", () => {
	it("saved settings are visible", () => {
		saveSettings({ serverUrl: "http://a", token: "t" });
		expect(getSettings()?.serverUrl).toBe("http://a");
	});
});